JP2791709B2 - Excavation control method of shield machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a method of controlling excavation of a shield machine used when constructing a tunnel underground. In order to make effective use of the underground space and the complicated roof tiles whose stability is relatively difficult to manage, the excavation of rocks at large depths where it is difficult to predict the soil quality of the stratum is performed quickly and stably. The present invention relates to a method for controlling the excavation of a shield machine to be obtained.

(Prior Art) In a conventional earth pressure shield, as a method of excavation control for maintaining stable and even stable excavation, earth pressure management, additive injection management, earth removal management, and the like are related to each other. Has been done.

In other words, there is earth pressure control as a direct method of stabilizing the face, and excavated earth or a mixture of the excavated earth and the additive is filled in the face chamber and the screw conveyor, and the pressure in the face chamber is propelled by the propulsion of the shield jack. The face is suppressed by countering the earth pressure and groundwater pressure of the ground acting on the face.

In this case, the pressure in the face chamber is constantly measured by an earth pressure gauge provided in the face chamber, and the detected pressure value is set within a range of a lower limit value at which the ground does not collapse and an upper limit value at which the ground does not rise. Excavation management is performed by adjusting the propulsion speed of the shield jack, the number of revolutions of the screw conveyor, and the like so as to balance the excavated soil amount and the earth removal amount so as to maintain a static earth pressure that does not cause deformation.

At this time, it is a necessary condition that the excavated earth and sand filled and pressurized in the face chamber and the screw conveyor has appropriate plastic fluidity and water impermeability.

Conventionally, as this excavation management, a control width of the resistance torque value of the rotary cutter provided in the shield machine is set, and an additive is appropriately injected into excavated earth and sand so as to maintain this as an integrated value,
They are mechanically kneaded to convert the soil properties to the above soil properties. Confirmation of the conversion effect is performed by observing the above-mentioned rotary cutter torque value and soil removal properties, and excavation management is performed while feeding back the results to excavation.

Also, as another method, a plurality of pressure gauges are attached from the front to the back of a soil discharging device such as a screw conveyor,
There is also a method in which the internal pressure is measured through each of these pressure gauges, and the properties of the internal filling sediment are estimated based on the pressure difference.

(Problems to be Solved by the Invention) However, the confirmation of the conversion effect due to the injection and kneading of the additive into the excavated earth and sand can be determined by the kneading resistance torque value. It is the sum of the resistance torque and the kneading resistance torque, and since the cutting resistance torque varies depending on the excavated soil, excavation speed, etc., it is insufficient to detect an accurate kneading resistance torque value and confirm the kneading effect. there were.

As described above, the method of checking the kneading effect only by the rotating cutter resistance torque is inaccurate in the excavation management, and it is difficult to keep the properties of the kneaded earth constantly uniform at all times. Alternatively, there was a risk of eruption of earth and sand from the discharge port.

In addition, it is more difficult to perform reliable management and mechanical operation when excavating a complicated tile layer in which the stratum of the excavation ground changes drastically. Especially, under high water pressure, eruption from the earth removal device is likely to occur. was there.

Furthermore, especially at a large depth, for example, it is difficult to perform an accurate soil survey in advance, and it is difficult to accurately grasp the properties of the ground to be excavated, so that appropriate excavation management is difficult.

In addition, in the conventional example in which a plurality of pressure detectors are provided in the discharging device in order to cope with such a situation, even if the eruption is predicted in advance, the characteristic of the pressure distribution immediately before the blasting is ultimately the characteristic of the discharging device. Appearing at the rear, the eruptive sediment has reached near the discharge port,
There is a drawback that an eruption will occur shortly after dealing with it, and there has been a problem that strict excavation management cannot be performed.

The present invention has been proposed in view of the above, and an object of the present invention is to excavate earth pressure shields, and to excavate earth and sand filled and pressurized in a cutting room and a screw conveyor during excavation, even in all grounds, in any ground. It is an object of the present invention to provide a method of controlling the excavation of a shield machine, which can surely and uniformly maintain the properties of a shield machine and can quickly construct a shaft.

(Means for Solving the Problems) In the excavation control method of the shield machine according to the present invention, the inside of the face chamber and the inside of the earth discharging device connected to the face chamber are filled with mud made of a mixture of excavated earth and sand, In the excavation control method of the shield machine by the earth pressure type shield machine which holds the face with the pressure of the mixture, a face chamber earth pressure gauge for detecting the pressure in the face chamber is provided, and approximately 1/2 of the total length of the earth discharging device is provided.
A plurality of earth removal devices in the front portion are provided, and the pressure in the face room and the pressure in the earth removal device are detected by the face room soil pressure meter and the earth removal device soil pressure meter, and the detected value of the face room soil pressure meter is detected. Is compared with a control value set in advance, the pressure in the face chamber is adjusted within a control width by increasing or decreasing the speed of a shield jack or a screw conveyor of the earth removal device, and the face chamber earth pressure gauge and the earth removal device are adjusted. Compare the pressure gradient obtained from the detected value of the earth pressure gauge with a preset management pressure gradient, and if the pressure gradient is gentle, increase the additive,
When the pressure gradient is steep, the additive is reduced to control the plastic fluidity of the mixture within a certain range so as to control the excavation, thereby achieving the above object.

(Operation) In the face room and the earth removal device, the earth and sand mixed with the excavated earth and the additive is converted into a so-called “mud” having properties of plastic fluidity and water impermeability and is filled under pressure. . In this case, in order to maintain the properties of the excavated earth and sand filled in the face chamber and the earth removal device uniformly and to maintain stable excavation, the present invention detects the pressure in the face chamber as described above. The difference between the pressure values detected by the earth pressure gauge and the earth pressure gauge installed in the front of the earth removal equipment, and the management of the excavation of the shield machine to keep the pressure gradient constant, For example, in the case of explosive sediment, it is possible to know it at the front of the earth removal device, so there is ample time before the earth and sand is discharged, and It is possible to take measures such as reducing to

(Embodiment 1) FIGS. 1 and 2 show a first embodiment of the present invention, of which FIG. 1 shows the overall configuration of an earth pressure shield machine of the present invention. In the drawing, reference numeral 1 denotes a shield machine, which is provided with a rotary cutter 2 having a well-known structure which is rotatable forward and backward via a cutter motor 11 provided on the inner side of the mine at the front thereof. Reference numeral 3 denotes the cutter bit, and reference numeral 5a denotes a partition wall provided in the front part of the shield tube 1a.
The hood portion 1a and the partition wall 5a define a cutting face room 5 for taking in the excavated earth 4 in front of the shield tube 1a. 7
Is an earth removal device such as a screw conveyor, in which a screw conveyor 9 is provided in a casing 8 and a front portion is connected to a lower central portion of a partition wall 5a so as to take in the excavated earth and sand 4 in the cutting face room 5. And a screw conveyor motor behind it for driving the screw conveyor 9
10 is provided, and a discharging port 12 is provided at the lower rear,
The earth discharging 6 is performed from the earth discharging port 12.

The casing 8 of the discharging device 7 is provided with a plurality of discharging device earth pressure gauges 15a to 15c for detecting the internal pressure at appropriate intervals. That is, these earth removal devices earth pressure gauges 15a to 15c are provided along the length direction of the earth removal device 7.

In addition, 13 is a shield jack for propulsion, 14 is a partition wall 5a
Face earth pressure gauge for detecting the pressure in the face chamber 5 provided in the section, 16 is a segment sequentially assembled with the excavation of the shield machine 1, and 17 is disposed corresponding to the discharge port 12 of the discharge device 7. Zuritro, G, is the ground.

 The outline of the operation of the shield machine 1 is as follows.

Now, by driving the cutter motor 11, the ground G is excavated by the cutter bit 3 attached to the rotary cutter 2, and the excavated earth 4 or a kneaded mixture with an additive injected in an appropriate amount from the inside of the machine is used to cut the ground G. The inside face and the inside of the earth removal device 7 are filled with pressure to hold the face F, and excavation is performed while discharging the earth removal amount corresponding to the excavated soil amount through the earth removal device 7.

As described above, the earth discharging device 7 is provided with several earth discharging pressure gauges 15a to 15c for detecting the internal pressure at suitable positions.
The pressure of the internally filled earth and sand 4a during excavation is constantly detected.

FIG. 2 shows the position of the earth pressure gauge S attached to the earth discharging device 7 of the shield machine used for the excavation experiment and the earth discharging port from the tip of the earth discharging device 7.
It is a schematic sectional drawing of the principal part which shows the state which modeled the relationship of the distance to 12.

In the experiment, an earth pressure type semi-shielding machine with a machine diameter of 1600 mm equipped with a screw conveyor with a blade diameter of 218 mm and a pitch of 170 mm was used. In this case, from the tip of the earth removing device 7, each earth removal apparatus at the position of _{L 1, L 2, L 3} , L 4, L 5, L n 7
Soil pressure gauge S ₁ for detecting the pressure inside _{the, S 2, S 3, S} 4, S 5, S n
Is installed. Distance from the screw conveyor tip to the mounting position of the soil pressure gauge S ₁ to S _n are each L ₁ = 101mm, L
_{2 = 301mm, L 3 = 629mm} , L 4 = 958mm, L 5 = 1286mm, L n = 16
15mm. The distance between S ₁ and S _2, and the distance between S _{1 and} S ₃ are approximately 0.9 times the blade diameter of the screw conveyor and 2.4 times, respectively.
Doubled. Also, S ₁ , S ₂ ...
a, 15b ... are supported.

The distribution state of the internal pressure of the earth discharging device 7 from the blade chamber 5 to the earth discharging port 12 of the earth discharging device 7 in the excavation of the earth pressure shield is based on the case where the earth discharging device 7 such as the screw conveyor 9 is used. In a stable excavation, the earth pressure gradually decreases as approaching the discharge port 12 and the face room 5 to the discharge port 12
It is known that the pressure distribution between them becomes almost linear.
This indicates that the screw conveyor 9 has a mountain retaining function.

Figure 3 uses a screw conveyor 9 to earth removing device 7 as described above, soil pressure shield installed soil pressure gauge S ₁ to S _n to the casing 8 of the earth removal apparatus 7 as schematically in Figure 2 FIG. 4 schematically shows a result of earth pressure measurement inside the earth removal device in the sand layer excavation experiment of FIG.

Note that this is the uniformity coefficient U at which the face water pressure 5 kg / cm ² acts.
It is the excavation experiment result in the fine sand layer of c = 1.9. In this figure, a range A surrounded by hatching is a stable pressure distribution in the excavated state, a dashed line a is a pressure distribution state immediately before the excavated earth and sand is erupted from the discharge port 12, and a dotted line b is This is a pressure distribution state that tends to be blocked in the screw conveyor.

As is clear from FIG. 3, in the excavation experiment,
In the state where the inside of the face chamber 5 and the screw conveyor 9 are filled with mud converted into a property having appropriate plastic fluidity and water impermeability, that is, during stable excavation, the pressure inside the screw conveyor 9 is discharged. gradually decreases toward the mouth 12, respectively P ₁ ~ the detected value with earth pressure gauge S ₁ to S _n
If _Pn , the pressure distribution between the face chamber 5 and the discharge port 12 is 0.3 to
Although there was a distribution of 0.7 kgf / cm ² , it was confirmed that the area between P _{1 and} P _n was almost linear.

Furthermore, when the fluidity of the mud was excessively increased by excessively injecting and kneading the additive from a stable excavation state, a phenomenon of spouting of earth and sand from the discharge port 12 of the screw conveyor 9 occurred.

The situation leading up to the eruption can be seen in Fig. 3,
First, it can be seen that the pressure distribution fluctuates at the tip of the screw conveyor 9. That is, paying attention to the measured values of the earth pressure gauges S ₁ and S ₂ at the tip of the screw conveyor 9, and assuming that the pressure difference is ΔP = P ₁ −P ₂ , the pressure of S ₂ increases immediately before the ejection. Thus, the pressure difference ΔP tended to gradually decrease.

Moreover, by reducing the additive injection amount, when lowering the fluidity of the mud, the resistance torque of the rotary cutter 2 is increased, it is closed slightly in the screw conveyor 9, the pressure drops of the soil pressure gauge S ₂ As a result, the pressure difference ΔP tended to increase.

Based on the above characteristics, in the present invention, the pressure at the tip of the earth removal device 7 is measured at several points, and the pressure difference (or pressure gradient) is measured.
Is maintained within a certain range, it is possible to maintain the properties of the mud in the face chamber 5 and the earth removal device 7 uniformly, and to block the inside of the earth removal device 7 or to eject the water from the earth discharging port 12. By predicting the phenomena in advance and dealing with them with sufficient time, troubles are prevented beforehand and stable excavation can be performed.

Therefore, in the illustrated example of FIG. 2, a plurality of earth pressure gauges S ₁ to S ₁ are arranged from the front in the longitudinal direction of the earth discharging device 7 to the front of the earth discharging port 12.
Showed that provided S _n, soil pressure gauge S ₁ of the front part only of the earth removing device 7, S _2, or may be performed excavation managed using S ₁ to S _3. Therefore, as shown in FIG.
It is good also as composition provided with 15a-15c only in the front part of earth removal device 7.

FIG. 4 shows an example of a flow diagram of the excavation in the present invention, in which symbols S / J are shield jacks, S / C is a screw conveyor, ΔPc is a control pressure difference at the front of the screw conveyor, ΔP _min Is the lower limit of ΔPc, ΔP _max
Indicates the upper limit of ΔPc, and ΔPe indicates the pressure difference at the front of the screw conveyor during actual excavation.

As described above, in the present invention, the properties of the mud in the face chamber 5 can be confirmed by the pressure difference ΔP at the front part of the screw conveyor 9, and this pressure difference ΔP is within a certain range (management width) in which a stable excavation state is achieved. The excavated earth and sand 4 becomes mud of uniform properties at all times by appropriately controlling the injection of the additive so that the cutter torque is excessive and the earth is clogged in the earth discharging device 7, or the earth and sand is ejected from the earth discharging port 12. Stable excavation management can be performed without emission.

In addition, if the management width of the pressure difference is set with a margin within a value at which blockage or eruption is predicted, more stable excavation management can be performed.

However, according to the present invention, even if the predictive value of blockage or eruption is reached during excavation, the sediment of that property only reaches the front of the screw conveyor 9, and these phenomena can be detected more quickly. As a result, early prevention measures are possible.

For example, if the blockage is predicted, the fluidity of the earth and sand in the face room 5 is too small, so that the speed of the shield jack 13 and the rotation of the screw conveyor 9 are stopped, the excavation and discharge are stopped, and an appropriate amount of additive is added. May be injected into the face chamber 5 and kneaded with the excavated earth and sand 4 to restore the fluidity. If eruption is predicted, the fluidity of the earth and sand in the face room 5 is excessive, so that the screw conveyor 9 to stop the earth removal, and to raise the internal pressure of the face chamber 5 to about the face pressure (passive earth pressure) which does not deform the ground G, to consolidate and dewater the soil in the face chamber. As a result, it is possible to restore the fluidity to an appropriate level, and it is possible to carry out stable excavation without trouble in earth removal.

In the above embodiment, the pressure difference value between the earth pressure gauges S ₁ and S ₂ is taken, but instead of the pressure difference value between S ₁ and S ₂ , S _{1 to} S ₃
Good results were also obtained by controlling the pressure difference between the two.

Further, the same operation and effect can be obtained by controlling the pressure gradient M = ΔP / (L ₂ −L ₁ ) = (P ₂ −P ₁ ) / (L ₂ −L ₁ ) instead of the pressure difference value ΔP. be able to. Furthermore, it is also possible to carry out excavation management while monitoring the pressure difference or pressure gradient by comparing detection values of a single soil pressure gauge of the front portion and the pressure of the working face chamber of the soil pressure gauge S ₁ to S _n .

Also, although not shown, a hollow cylinder having a discharge opening at the rear is connected to the face chamber to form an earth removal device. Even in a shield machine that fills the mixture and suppresses the face by resisting the earth pressure and the groundwater pressure acting on the face by the frictional force between the filled earth and sand and the inner surface of the soil removal device, the pressure distribution inside the soil removal device is also reduced. It gradually decreases as you approach Dochiguchi.

Therefore, even in the above-mentioned shield machine, if the present invention is used, the pressure difference or the pressure gradient in front of the discharging device can be kept constant, and the discharging characteristics can be managed uniformly, and the problem of discharging problems can be solved. No stable excavation can be performed.

Embodiment 2 FIGS. 5 (a) and 5 (b) show a second embodiment of the present invention. In this embodiment, the earth pressure gauge 15a is provided on the screw shaft 9a of the screw conveyor 9 as described above. It is different from the example.

Other configurations and operations are the same as those of the first embodiment. Note that the earth pressure gauge 15a can be provided on the screw blade 9b.

(Effect of the Invention) As described above, in the excavation control method for a shield machine according to the present invention, a face chamber pressure gauge for detecting pressure in the face chamber is provided.
Provide a plurality of earth pressure gauges in the front part within approximately 1/2 of the total length of the earth removal device, and detect the pressure in the face chamber and the pressure in the earth removal device by the face room earth pressure gauge and the earth removal device, The pressure in the face chamber is adjusted to within the control width by increasing or decreasing the speed of the screw conveyor of the shield jack or the earth removal device by comparing the detected value of the face room soil pressure gauge with a preset control value, and the face chamber soil pressure gauge and Compare the pressure gradient determined from the detected value of the earth removal device earth pressure gauge with a preset management pressure gradient, if the pressure gradient is gentle, increase the additive,
When the pressure gradient is steep, the additive is reduced to control the plastic fluidity of the mixture within a certain range and excavation control is performed, so the properties of the mud in the face chamber and in the earth removal device are clarified. It is easy to understand and manage excavation at large depths where it is difficult to survey complicated soil layers and soils. It can detect signs of obstruction etc. sooner,
Since it is possible to cope with the situation earlier, troubles can be prevented in advance, and the drilling can be performed smoothly.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a first embodiment of the present invention, FIG. 2 is a schematic sectional view of a first embodiment of the present invention, FIG. 3 is a schematic diagram of a pressure distribution in an earth removal device of the present invention, and FIG. Example of excavation management flow diagram,
FIG. 5A shows another embodiment of the present invention, and FIG. 5B shows a cross-sectional view taken along line AA in FIG. DESCRIPTION OF SYMBOLS 1 ... Shield machine 1a ... Shield cylinder 2 ... Rotary cutter 3 ... Cutter bit 4 ... Excavation earth and sand 5 ... Face chamber 5a ... Partition wall 6 ... Discharge 7 ... Discharge device 8 ... Casing 9 …… Screw conveyor 9a …… Screw shaft 10 …… Screw conveyor motor 11 …… Rotary cutter motor 12 …… Ejection port 13 …… Shield jack 14 …… Soil pressure gauge in the face room 15a ～ 15c …… Soil pressure meter in the earth removal device 16 …… Segment 17 …… Zuritro

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masakatsu Mochizuki 1-24-4 Shinkawa, Chuo-ku, Tokyo Inside Daitoyo Construction Co., Ltd. (72) Inventor Katsuhiko Miyamoto 1-24-4 Shinkawa, Chuo-ku, Tokyo Otoyo Construction Co., Ltd. (72) Inventor Takeki Kishi 1-24-4 Shinkawa, Chuo-ku, Tokyo Taitoyo Construction Co., Ltd. (56) References JP-A-61-17697 (JP, A) JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) E21D

Claims (1)

(57) [Claims] An earth pressure type shield machine which fills a face chamber and an earth discharging device connected to the face chamber with a mixture of excavated earth and sand and an additive, and holds the face with the pressure of mud made of the mixture. In the excavation control method of the shield machine, a face chamber earth pressure gauge for detecting the pressure in the face chamber is provided, and a plurality of earth removal apparatus earth pressure gauges are provided at a front portion within approximately 1/2 of the entire length of the earth removal apparatus, Detecting the pressure in the face chamber and the pressure in the earth removal device by the face room earth pressure meter and the earth removal device earth pressure meter, comparing the detected value of the face room earth pressure meter with a preset management value, and using a shield jack or the earth removal device. The pressure in the face chamber is adjusted within the control range by increasing or decreasing the speed of the screw conveyor of the device, and the pressure gradient determined in advance from the detected values of the face room soil pressure gauge and the earth removal device soil pressure gauge is set to a predetermined control pressure. Devil In comparison with, when the pressure gradient is gentle, the additive is increased, and when the pressure gradient is steep, the additive is reduced, thereby controlling the plastic fluidity of the mixture within a certain range and controlling excavation. A method of controlling excavation of a shield machine characterized by the following.